The development and use of intelligent credit cards, "smart cards" or "IC cards" is well-known. These devices are made by encasing one or more microelectronic chips in a plastic carrier the size of a credit card. The card generally includes a non-volatile memory for the storage of primary encoded data, and some cards include a CPU chip for limited processing of that data.
With the advent of recent advances in microelectronics, it is now possible to put a vast amount of computing power and memory right in the IC card. The card could, therefore, carry personal identification data to virtually eliminate fraudulent use, such data as personal characteristics, driver's license, social security number, personal identification numbers, and even a voice print. The card could also carry the account numbers of all the owner's charge accounts, the balances of all accounts, credit limits and, for example, other information such as telephone directories, medical information and any other information.
IC cards are considered to be more secure and versatile than the standard embossed plastic credit cards, which employ a magnetic stripe for the storage of data. Virtually all data cards in the past have had an electrical connector which mates a connector with a reader/programmer unit. The reader/programmer unit supplies the card with power and communicates with the card's internal circuitry through electrical connector. The electrical connector on the card is subject to wear due to the frictional contact that must be maintained with the connector in the reader/programmer. As the card is used for a period of time, dirt or grit deposits on the connector terminals make any electrical connection sporadic or ineffective, rendering the card unusable.
One problem that arises if metallic contacts are used, however, is increased ohmic resistance due to the oxidation that takes place over time on the contact surfaces. This is of concern since the accuracy of the data transfer between the card and a Read/Write device decreases as the ohmic resistance of these contacts increases. In addition, the contacts while in the exposed position allow air-borne particles to deposit on the surfaces, decreasing the contact area and causing intermittent connection. Inasmuch as operating power for reading and writing onto a card is also transferred from an associated station in the system to the card via these contacts, there is a loss in the amount of energy transferred after some time, rendering the card inoperative.
A second problem associated with the use of a direct contact device for data transfer to the smart cards is the possibility of electrostatic discharge (ESD) occurring which can damage the microelectronics on the card. High voltages that build up on a person or card that are inadvertently coupled thereto from other sources may very easily be coupled directly to the electronics on the card when metallic contacts are used. Clamping diodes employed at the various inputs of a card provide some measure of protection but are not capable of protecting against some of the high voltage levels a card might occasionally encounter during normal use in its expected environment.
The terminals may also take the form of optical data transmission and reception devices. Optical type terminals may also be susceptible to conducting static electrical discharges onto the storage module. Also, the radiation transmission and reception device such as a lens, must be maintained for radiation absorbing contaminants, such as dirt and grease.
Due to the requirement of previous data storage modules, that the data coupling terminals be in physical contact or otherwise physically accessible to the system's mating terminals, the exposure of the terminals on a surface of the data storage module can result in an overall degradation of the operation of the module or even the complete failure of the module to reliably store data. This problem is especially acute in relatively small data storage cards, which by definition, may be inserted and removed a number of times from a system. Such cards may also be especially vulnerable in that they are typically carried about in a jacket or shirt pocket where the danger of exposure to static discharge is increased.
Another problem is that most data cards have a fragile construction which is inadequate to protect the internal microelectronics during long term use. Should the data card become exposed to temperature extremes of hostile environments, the data could be damaged or lost. If this card contains a patient's medical records, such data loss could be catastrophic. Moreover, when the data cards are plugged in or removed from a reader/programmer, electrical sparks can result, which limits their use to environments that are free of flammable or explosive gases.
A final problem with previous IC or smart cards is with respect to those powered by batteries and having moving parts. This causes the problem of the user needing to know when the battery was low and how to change the battery. The problem with the moving parts was that moving parts tended to wear out and to render the card inoperative at inopportune times.